Clairex "photomod" LDR

[Freq Band]

Are these useful for any projects here ?
Uses an internal lamp, not an LED.

Clairex CL5H10A
http://www.datasheetarchive.com/pdf/1041839.pdf
Lamp at a few milliamps, photo-resistor measured:

0v = INF
72mv = 330meg
1.5v = 10 meg
5v = 4,2k
10v = 450R

and CL 1030 M (no pdf found)
0v = INF
72mv = INF
1.5v = 200 meg
5v = 3.6k
10v = 500R


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[dale116dot7]

Sounds like one of the later Altec compressors might use something like that - I can't remember which one but it was solid-state and used an incanescent lamp and photocell. I would guess, slow, but maybe useful for something. I would think either a compressor, or maybe a 'slowerizer' - something like a gate but with a slow response like that, things would kinda 'fade in'.

-Dale

 

[Freq Band]

LA2A perhaps ?


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[SSLtech]

LA2a -Negative.

EL panel.

 

[CJ]

Vibrato "Roach"
And I don't mean a hooch roach.
Bong only. Roaches are a thing of the past.
Volcano if you are a grower.
search "volcano vaporizer"


search: "vibrato roach"

if you no believe.
OT: last nite dreaming of V76-LA2a all in one box, one bigass pcb, (mercy on my sole P to P freaks!)
Best vocal chain around-sans U67.


What say?

 

[JohnRoberts]

I don't recall independent duals but I did work with some center-tapped elements in an attempt to linearize the control law.

I would ground the center-tap, and close the loop on the lamp drive to realize a target resistance on the half that I was measuring. The other half was free to be used as a voltage controlled variable resistance to ground in audio circuits.

With this technique I could pretty accurately regulate the resistance over a fair range but typical opamp input voltage offsets of the time compromised the accuracy for very small DC voltages, making the log control law of VCAs more attractive over large ranges.

I forget all the details of why I abandoned LDRs, but I settled on DBX or Buff's VCAs, for high performance paths, and 3080, or the later ne570/ne572 for less critical applications.

JR

 

[Freq Band]

Would the "lamp" type have any advantage over the LED type, used as a basic line attenuator (replacement for a pot) ??
I would imagine for stereo, careful matching would be in order.


More Raysistors :

And some VERY old vactrols :

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[Freq Band]

Where do you find this stuff? Mine were from my brother's surplus electronics store circa 1980 and were hidden in a box for the last 30 years.

I found them in a 50 yo electronics surplus store, at the bottom of 30 yo boxes.
Ha ! ...I guess this is where the hibernate. Haven't seen "the light" for many years.

I do have modern vactrols, as well as several old and new photo cells, waiting to be paired with LEDs....
....waiting......

Probably for some synth modules.

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[Freq Band]

Apex Surplus, Los Angeles.
http://www.apexelectronic.com/

also, Steve here has his store....
http://www.apexjr.com/
He has a lot of stuff not listed on his site, call him.

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